1. Field of the Invention
The present invention relates to an apparatus for and a method of controlling driving of a motor, which is not exclusively but preferably adapted for use in a vehicle, when the motor for the vehicle is driven by a drive circuit capable of operating according to a pulse width modulation (PWM) signal.
2. Description of the Related Art
Japanese Laid-Open (Kokai) Patent Application Publication No. 1993(H05)-213207 discloses an electric power steering apparatus using a motor driven according to a PWM signal.
Japanese Laid-Open (Kokai) Patent Application Publication No. 1993(H05)-292042 discloses such an art that in a communication apparatus of a PWM signal, a deviation of a pulse width generating during a transmitting and receiving process is detected and correction of the pulse width of the received PWM modulated data pulse is made based on the deviation.
Herein, according to the communication apparatus disclosed in Japanese Laid-Open (Kokai) Patent Application Publication No. 1993(H05)-292042, it is possible to accurately transmit and receive the PWM signals.
However, when driving of the motor for the vehicle is conducted by controlling the driving circuit based on the PWM signal, duty of a signal outputted from the driving circuit must become different from duty of the PWM signal due to heat generation of the driving circuit or dispersion of characteristics among respective driving circuits, so that control accuracy in controlling of driving of the motor must be lowered.